.\" Copyright (c) 2005-2006 Yura Pakhuchiy.
.\" Copyright (c) 2005 Richard Russon.
.\" Copyright (c) 2006-2009 Szabolcs Szakacsits.
.\" Copyright (c) 2009-2014 Jean-Pierre Andre
.\" This file may be copied under the terms of the GNU Public License.
.\"
.TH NTFS-3G 8 "Aug 2021" "ntfs-3g @VERSION@"
.SH NAME
ntfs-3g \- Third Generation Read/Write NTFS Driver
.SH SYNOPSIS
.B ntfs-3g
\fB[-o \fIoption\fP\fB[,...]]\fR
.I volume mount_point
.br
.B mount \-t ntfs-3g
\fB[-o \fIoption\fP\fB[,...]]\fR
.I volume mount_point
.br
.B lowntfs-3g
\fB[-o \fIoption\fP\fB[,...]]\fR
.I volume mount_point
.br
.B mount \-t lowntfs-3g
\fB[-o \fIoption\fP\fB[,...]]\fR
.I volume mount_point
.SH DESCRIPTION
\fBntfs-3g\fR is an NTFS driver, which can create, remove, rename, move
files, directories, hard links, and streams; it can read and write files,
including streams, sparse files and transparently compressed files; it can
handle special files like symbolic links, devices, and FIFOs; moreover it
provides standard management of file ownership and permissions, including
POSIX ACLs.
.PP
It comes in two variants \fBntfs-3g\fR and \fBlowntfs-3g\fR with
a few differences mentioned below in relevant options descriptions.
.PP
The \fIvolume\fR to be mounted can be either a block device or 
an image file, either by using the mount command or starting the drive.
.SS Windows hibernation and fast restarting
On computers which can be dual-booted into Windows or Linux, Windows has
to be fully shut down before booting into Linux, otherwise the NTFS file
systems on internal disks may be left in an inconsistent state and changes
made by Linux may be ignored by Windows.
.P
So, Windows may not be left in hibernation when starting Linux, in order
to avoid inconsistencies. Moreover, the fast restart feature available on
recent Windows systems has to be disabled. This can be achieved by issuing
as an Administrator the Windows command which disables both
hibernation and fast restarting :
.RS
.sp
powercfg /h off
.sp
.RE
If either Windows is hibernated or its fast restart is enabled, partitions
on internal disks are forced to be mounted in read-only mode.
.SS Access Handling and Security
By default, files and directories are owned by the effective 
user and group of the mounting process, and everybody has
full read, write, execution and directory browsing permissions.
You can also assign permissions to a single user by using the
.B uid
and/or the
.B gid 
options together with the 
.B umask,
or
.B fmask
and
.B dmask
options.
.PP
Doing so, all Windows users have full access to the files created by 
.B ntfs-3g.
.PP
But, by setting the \fBpermissions\fR option, you can benefit from the full
ownership and permissions features as defined by POSIX. Moreover, by defining
a Windows-to-Linux user mapping, the ownerships and permissions are even
applied to Windows users and conversely.
.PP
If 
.B ntfs-3g 
is set setuid-root then non-root users will 
be also able to mount volumes.
.SS Windows Filename Compatibility
NTFS supports several filename namespaces: DOS, Win32 and POSIX. While the
\fBntfs-3g\fR driver handles all of them, it always creates new files in the 
POSIX namespace for maximum portability and interoperability reasons. 
This means that filenames are case sensitive and all characters are
allowed except '/' and '\\0'. This is perfectly legal on Windows, though
some application may get confused. The option \fBwindows_names\fP may be
used to apply Windows restrictions to new file names.
.SS Alternate Data Streams (ADS)
NTFS stores all data in streams. Every file has exactly one unnamed
data stream and can have many named data streams.  The size of a file is the
size of its unnamed data stream.  By default, \fBntfs-3g\fR will only read
the unnamed data stream.
.PP
By using the option \fBstreams_interface=windows\fP, with the ntfs-3g driver
(not possible with lowntfs-3g), you will be able to read any named data
streams, simply by specifying the stream name after a colon.
For example:
.RS
.sp
cat some.mp3:artist
.sp
.RE
Named data streams act like normal files, so you can read from them, write to
them and even delete them (using rm).  You can list all the named data streams
a file has by getting the \fBntfs.streams.list\fP extended attribute.
.SH OPTIONS
Below is a summary of the options that \fBntfs-3g\fR accepts.
.TP
.B acl
Enable setting Posix ACLs on created files and use them for access control.
This option is only available on specific builds. It is set by default
when a user mapping file is present and the
.B permissions
mount option is not set.
.TP
.B allow_other
This option overrides the security measure restricting file access
to the user mounting the filesystem. This option is only
allowed to root, but this restriction can be overridden by
the \fBuser_allow_other\fP option in the /etc/fuse.conf file.
.TP
.B atime, noatime, relatime
The 
.B atime 
option updates inode access time for each access.

The 
.B noatime 
option disables inode access time updates, which can speed up
file operations and prevent sleeping (notebook) disks spinning 
up too often thus saving energy and disk lifetime.

The
.B relatime 
option is very similar to 
.B noatime. 
It updates inode access times relative to modify or change time. 
The access time is only updated if the previous access time was earlier 
than the current modify or change time. Unlike
.B noatime
this option doesn't break applications that need to know 
if a file has been read since the last time it was modified.
This is the default behaviour.
.TP
.B big_writes
This option prevents fuse from splitting write buffers into 4K chunks,
enabling big write buffers to be transferred from the application in a
single step (up to some system limit, generally 128K bytes).
.TP
.B compression
This option enables creating new transparently compressed files in
directories marked for compression. A directory is marked for compression by
setting the bit 11 (value 0x00000800) in its Windows attribute. In such a
directory, new files are created compressed and new subdirectories are
themselves marked for compression. The option and the flag have no effect
on existing files. Currently this is the default option.
.TP
.B debug
Makes ntfs-3g (or lowntfs-3g) to print a lot of debug output from libntfs-3g
and FUSE.
.TP
.B delay_mtime[= value]
Only update the file modification time and the file change time of a file
when it is closed or when the indicated delay since the previous update has
elapsed. The argument is a number of seconds, with a default value of 60.
This is mainly useful for big files which are kept open for a long
time and written to without changing their size, such as databases or file
system images mounted as loop.
.TP
.BI dmask= value
Set the  bitmask of the directory permissions that are not
present. The value is given in octal. The default value is 0 which
means full access to everybody.
.TP
.B efs_raw
This option should only be used in backup or restore situation.
It changes the apparent size of files and the behavior of read and
write operation so that encrypted files can be saved and restored
without being decrypted. The \fBuser.ntfs.efsinfo\fP extended attribute
has also to be saved and restored for the file to be decrypted.
.TP
.BI fmask= value
Set the  bitmask of the file permissions that are not present. 
The value is given in octal. The default value is 0 which
means full access to everybody.
.TP
.B force
This option is obsolete. It has been superseded by the \fBrecover\fR and
\fBnorecover\fR options.
.TP
.B hide_dot_files
Set the hidden flag in the NTFS attribute for created files and directories
whose first character of the name is a dot. Such files and directories
normally do not appear in directory listings, and when the flag is set
they do not appear in Windows directory displays either.
When a file is renamed or linked with a new name, the hidden flag is
adjusted to the latest name.
.TP
.B hide_hid_files
Hide the hidden files and directories in directory listings, the hidden files
and directories being the ones whose NTFS attribute have the hidden flag set.
The hidden files will not be selected when using wildcards in commands,
but all files and directories remain accessible by full name, for example you
can always display the Windows trash bin directory by :
"ls \-ld '$RECYCLE.BIN'".
.TP
.B ignore_case \fP(only with lowntfs-3g)
Ignore character case when accessing a file (\fBFOO\fR, \fBFoo\fR, \fBfoo\fR,
etc. designate the same file). All files are displayed with lower case in
directory listings.
.TP
.B inherit
When creating a new file, set its initial protections
according to inheritance rules defined in parent directory. These rules
deviate from Posix specifications, but yield a better Windows
compatibility. The \fBpermissions\fR (or **acl**) option or a valid user
mapping file is required for this option to be effective.
.TP
.BI locale= value
This option can be useful when wanting a language specific locale environment.
It is however discouraged as it leads to files with untranslatable characters
to not be visible.
.TP
.BI max_read= value
With this option the maximum size of read operations can be set.
The default is infinite.  Note that the size of read requests is
limited anyway by the system (usually to 128kbyte).
.TP
.B no_def_opts
By default ntfs-3g acts as if \fBsilent\fP (ignore permission errors when
permissions are not enabled),
\fBallow_other\fP (allow any user to access files) and \fBnonempty\fP
(allow mounting on non-empty directories) were set, and \fBno_def_opts\fP
cancels these default options.
.TP
.B no_detach
Makes ntfs-3g to not detach from terminal and print some debug output.
.TP
.B nocompression
This option disables creating new transparently compressed files in directories
marked for compression. Existing compressed files can still be read and
updated.
.TP
.B norecover
Do not try to mount a partition which was not unmounted properly by Windows.
.TP
.B permissions
Set standard permissions on created files and use standard access control.
This option is set by default when a user mapping file is present.
.TP
.B posix_nlink
Compute the count of hard links of a file or directory according to
the POSIX specifications. When this option is not set, a count of 1
is set for directories, and the short name of files is accounted for.
Using the option entails some penalty as the count is not stored and
has to be computed.
.TP
.B recover
Recover and try to mount a partition which was not unmounted properly by
Windows. The Windows logfile is cleared, which may cause inconsistencies.
Currently this is the default option.
.TP
.B remove_hiberfile
When the NTFS volume is hibernated, a read-write mount is denied and
a read-only mount is forced. One needs either to resume Windows and
shutdown it properly, or use this option which will remove the Windows
hibernation file. Please note, this means that the saved Windows 
session will be completely lost. Use this option under your own 
responsibility.
.TP
.B ro
Mount the filesystem read\-only. Useful if Windows is hibernated or the
NTFS journal file is unclean.
.TP
.B show_sys_files
Show the metafiles in directory listings. Otherwise the default behaviour is
to hide the metafiles, which are special files used to store the NTFS
structure. Please note that even when this option is specified, "$MFT" may
not be visible due to a glibc bug. Furthermore, irrespectively of
\fBshow_sys_files\fP, all files are accessible by name, for example you can
always do
"ls \-l '$UpCase'".
.TP
.B silent
Do nothing, without returning any error, on chmod and chown operations
and on permission checking errors,
when the \fBpermissions\fR option is not set and no user mapping file
is defined. This option is on by default, and when set off (through option
\fBno_def_opts\fR) ownership and permissions parameters have to be set.
.TP
.BI special_files= mode
This option selects a mode for representing a special file to be created
(symbolic link, socket, fifo, character or block device). The \fImode\fP can
be \fBinterix\fR or \fBwsl\fR, and existing files in either mode are
recognized irrespective of the selected mode. Interix is the traditional
mode, used by default, and wsl is interoperable with Windows WSL, but
it is not compatible with Windows versions earlier than Windows 10.
Neither mode are interoperable with Windows.
.TP
.BI streams_interface= mode
This option controls how the user can access Alternate Data Streams (ADS) or in
other words, named data streams. The \fImode\fP can be set to one of \fBnone\fR,
\fBwindows\fR or \fBxattr\fR. If the option is set to \fBnone\fR, the user
will have no access to the named data streams. If it is set to \fBwindows\fR
(not possible with lowntfs-3g), then the user can access them just like in
Windows (eg. cat file:stream). If it's set to \fBxattr\fR, then the named
data streams are mapped to extended attributes and a user can manipulate them
using \fB{get,set}fattr\fR utilities. The default is \fBxattr\fR.
.TP
\fBuid=\fP\fIvalue\fP and \fBgid=\fP\fIvalue\fP
Set the owner and the group of files and directories. The values are numerical.
The defaults are the uid and gid of the current process.
.TP
.BI umask= value
Set the  bitmask of the file and directory permissions that are not
present. The value is given in octal. The default value is 0 which
means full access to everybody.
.TP
.BI usermapping= file-name
Use file \fIfile-name\fP as the user mapping file instead of the default
\fB.NTFS-3G/UserMapping\fP. If \fIfile-name\fP defines a full path, the
file must be located on a partition previously mounted. If it defines a
relative path, it is interpreted relative to the root of NTFS partition
being mounted.
.P
.RS
When a user mapping file is defined, the options \fBuid=\fP, \fBgid=\fP,
\fBumask=\fP, \fBfmask=\fP, \fBdmask=\fP and \fBsilent\fP are ignored.
.RE
.TP
.B user_xattr
Same as \fBstreams_interface=\fP\fIxattr\fP.
.TP
.B windows_names
This option prevents files, directories and extended attributes to be
created with a name not allowed by windows, because
.RS
.RS
.sp
- it contains some not allowed character,
.br
- or the last character is a space or a dot,
.br
- or the name is reserved.
.sp
.RE
The forbidden characters are the nine characters " * / : < > ? \\ | and
those whose code is less than 0x20, and
the reserved names are CON, PRN, AUX, NUL, COM1..COM9, LPT1..LPT9,
with no suffix or followed by a dot.
.sp
Existing such files can still be read (and renamed).
.RE
.SH USER MAPPING
NTFS uses specific ids to record the ownership of files instead of
the \fBuid\fP (user id) and \fBgid\fP (group id) used by Linux. As a
consequence a mapping between the ids has to be defined for ownerships
to be recorded into NTFS files and recognized.
.P
By default, this mapping is fetched from the file \fB.NTFS-3G/UserMapping\fP
located in the NTFS partition. The option \fBusermapping=\fP may be used
to define another location. When the option **permissions** is set and
no mapping file is found, a default mapping is used.
.P
Each line in the user mapping file defines a mapping. It is organized
in three fields separated by colons. The first field identifies a \fBuid\fP,
the second field identifies a \fBgid\fP and the third one identifies the
corresponding NTFS id, known as a \fBSID\fP. The \fBuid\fP and the \fBgid\fP
are optional and defining both of them for the same \fBSID\fP is not
recommended.
.P
If no interoperation with Windows is needed, you can use the option
\fBpermissions\fP to define a standard mapping. Alternately, you may define
your own mapping by setting a single default mapping with no uid and gid. In
both cases, files created on Linux will appear to Windows as owned by a
foreign user, and files created on Windows will appear to Linux as owned by
root. Just copy the example below and replace the 9 and 10-digit numbers by
any number not greater than 4294967295. The resulting behavior is the same as
the one with the option \fBpermission\fP set with no ownership option and no
user mapping file available.
.RS
.sp
.B ::S-1-5-21-3141592653-589793238-462643383-10000
.sp
.RE
If a strong interoperation with Windows is needed, the mapping has to be
defined for each user and group known to both system, and the \fBSID\fPs used
by Windows has to be collected. This will lead to a user mapping file like :
.RS
.sp
.B john::S-1-5-21-3141592653-589793238-462643383-1008
.B mary::S-1-5-21-3141592653-589793238-462643383-1009
.B :smith:S-1-5-21-3141592653-589793238-462643383-513
.B ::S-1-5-21-3141592653-589793238-462643383-10000
.sp
.RE
.P
The utility \fBntfsusermap\fP may be used to create such a user
mapping file.
.SH EXAMPLES
Mount /dev/sda1 to /mnt/windows:
.RS
.sp
.B ntfs-3g /dev/sda1 /mnt/windows
.RE
or
.RS
.B mount -t ntfs-3g /dev/sda1 /mnt/windows
.sp
.RE
Mount the ntfs data partition /dev/sda3 to /mnt/data with standard Linux
permissions applied :
.RS
.sp
.B ntfs-3g -o permissions /dev/sda3 /mnt/data
.RE
or
.RS
.B mount -t ntfs-3g -o permissions /dev/sda3 /mnt/data
.sp
.RE
Read\-only mount /dev/sda5 to /home/user/mnt and make user with uid 1000 
to be the owner of all files:
.RS
.sp
.B ntfs-3g /dev/sda5 /home/user/mnt \-o ro,uid=1000
.sp
.RE
/etc/fstab entry for the above (the sixth and last field has to be zero to
avoid a file system check at boot time) :
.RS
.sp
.B /dev/sda5 /home/user/mnt ntfs\-3g ro,uid=1000 0 0
.sp
.RE
Unmount /mnt/windows:
.RS
.sp
.B umount /mnt/windows
.sp
.RE
.SH EXIT CODES
To facilitate the use of the
.B ntfs-3g
driver in scripts, an exit code is returned to give an indication of the 
mountability status of a volume. Value 0 means success, and all other
ones mean an error. The unique error codes are documented in the
.BR ntfs-3g.probe (8)
manual page.
.SH KNOWN ISSUES
Please see 
.RS
.sp
https://github.com/tuxera/ntfs-3g/wiki/NTFS-3G-FAQ
.sp
.RE
for common questions and known issues.
If you would find a new one in the latest release of
the software then please post an ntfs-3g issue describing it in detail
so that the development team can be aware of the issue and take care of it:
.RS
.sp
https://github.com/tuxera/ntfs-3g/issues
.sp
.RE
.SH AUTHORS
.B ntfs-3g 
was based on and a major improvement to ntfsmount and libntfs which were
written by Yura Pakhuchiy and the Linux-NTFS team. The improvements were 
made, the ntfs-3g project was initiated and currently led by long time 
Linux-NTFS team developer Szabolcs Szakacsits (szaka@tuxera.com).
.SH THANKS
Several people made heroic efforts, often over five or more
years which resulted the ntfs-3g driver. Most importantly they are 
Anton Altaparmakov, Jean-Pierre André, Erik Larsson, Richard Russon,
Szabolcs Szakacsits,
Yura Pakhuchiy, Yuval Fledel, and the author of the groundbreaking FUSE
filesystem development framework, Miklos Szeredi.
.SH SEE ALSO
.BR ntfs-3g.probe (8),
.BR ntfsprogs (8),
.BR attr (5),
.BR getfattr (1)
